This invention relates to wireless communication and more particularly relates to such communication over a link in which one of the transmitters used for communication has a power transmission disadvantage compared to another transmitter used for communication over the link.
Bandwidth for wireless communication systems is a limited resource. Methods for efficient use of bandwidth are needed for satellite communications and cellular telephone communications. This invention addresses the need and provides a solution.
The preferred embodiment is useful in a wireless communication system employing a communication link between a first transmitter/receiver comprising a first power amplifier and a second transmitter/receiver comprising a second power amplifier. The second transmitter/receiver has a power transmitting disadvantage with respect to the first transmitter/receiver. In such an environment, the efficiency of the communication can be improved by generating first communication signals for transmission over the communication link from the first transmitter/receiver to the second transmitter/receiver. The first power amplifier is operated in a non-saturated mode of operation during transmission of the first communication signals to the second transmitter/receiver on the communication link. Second communication signals are generated for transmission over the communication link from the second transmitter/receiver to the first transmitter/receiver. The second power amplifier is operated in a saturated mode of operation during transmission of the second communication signals on the communication link to the first transmitter/receiver. The foregoing techniques can be used to advantage in wireless communication systems, such as a satellite communication system or a cellular telephone communication system.
By using the foregoing techniques in a satellite communication system, the satellite uplink requires less bandwidth than prior art symmetric systems. Bandwidth is a limited resource that is regulated internationally and often licensed for use at high cost. Thus, saving bandwidth on the uplink can:
1. reduce requirements for the limited bandwidth resource;
2. reduce cost;
3. allow allocation of more-bandwidth to downlink (by reducing uplink bandwidth), thereby allowing maximum data transmission from user terminal uplink to satellite and satellite downlink to user terminal; and
4. maximize possible revenue to satellite communication operators (billable bits) by using the foregoing techniques.